I'm at the end from having a cold but now have a ache in right side of back (mid) worse when take deep breath also feeling sick what could this be?

Chest/Back pain: I would suggest you probably have had a little pneumonia, probably viral, and have some pleuritic chest pain. It probably doesn't need treatment (other than ibuprofen) unless you get a fever or start coughing up nasty sputum

Need evaluation : As soon as possible. Your symptoms do suggest possible pleurisy and pneumonia. Especially if you have cough and fever.